Conventional algorithms use only numerical searching for anisotropy processing of cross-dipole acoustic waveforms, to minimize an objective function whose parameters are the azimuth angle of the X-dipole transmitter relative to the fast principal flexural wave axis, and a set of auxiliary parameters. The auxiliary parameters are used to characterize the received waveforms as functions of slowness and borehole radius, among others. Sometimes the processing is used to determine the location and amount of stress-induced anisotropy in a geological formation.